The first altar mentioned in the Word was the one built by Noah after he came out of the ark, after being saved from the great flood. On that altar, he sacrificed clean animals to the Lord.

Mountains represent the Lord because of their height; we need to raise our thoughts above worldly things when "talking" with the Lord. An altar is a small artificial mountain. When it's used in worship, it can call to mind this raising of thought. The fire and smoke that rise from an altar are symbolically being sent to the Lord.

Most altars were made from unhewn stones. Stones represent truths. Unhewn stones - ones that have not been shaped by men - represent truths from the Word, truths that have not been adulterated.

The clean beasts to be sacrificed represent good things, charitable acts done because they are right. The clean birds represent thoughts about doctrine and actions, and about what is right. Presenting these things is an acknowledgment that we have them from the Lord, and a giving thanks to Him for them.

In the Israelitish Tabernacle, the altar of burnt offering represented the acknowledgment of good and the altar of incense that of truth. For this reason this larger altar, which was outside by the door, was made of brass which signifies natural good, while the altar of incense was made of gold, which signifies love to the Lord from whom comes truth.

10155. 'And they will recognize that I am Jehovah their God' means perception that the Lord is the source of all good and all truth. This is clear from the meaning of 'recognizing' as understanding, believing, and perceiving, dealt with below. The reason why perceiving that the Lord is the source of all good and all truth is meant is that the names Jehovah and God are used, and the Lord is called Jehovah by virtue of good and God by virtue of truth, see 2586, 2769, 2807, 2822, 3921, 4287, 4402, 7010, 9167.

The reason why 'recognizing' means understanding, believing, and perceiving is that the word is used in reference both to the human power of understanding and to the power of will. When used in reference solely to the power of understanding it means understanding; when used in reference to the understanding and at the same time the will it means believing; and when used in reference solely to the will it means perceiving. With those therefore who merely know of something and as a result think about it, recognizing implies understanding. But with those who possess faith, recognizing implies believing, and with those who have love, recognizing implies perceiving.

[2] When however recognizing is coupled with understanding, seeing, or believing, 'recognizing' means perceiving; for understanding, seeing, and believing are connected with the understanding, consequently with truth, whereas perceiving is connected with the will, consequently with good, as in John,

Peter said, We have believed and recognized that You are the Christ, the Son of the living God. John 6:69.

In the same gospel,

Jesus said, Believe the works, that you may recognize and believe that the Father is in Me, and I in the Father. John 10:38.

In the same gospel,

Jesus said, If you recognize Me you recognize My Father, and from now on you recognize Him and have seen Him. John 14:7.

In the same gospel,

The Spirit of truth will be sent, whom the world cannot receive, because it neither sees Him nor recognizes Him. But you recognize Him, because He remains with you and will be in you. John 14:16-17.

In Mark,

Jesus spoke in parables, so that seeing they may see and not recognize. Mark 4:11-12.

In Jeremiah,

... that you may recognize and see that it is evil and bitter to depart from Jehovah your God. Jeremiah 2:19.

In the same prophet,

Let him who glories glory in this, to understand and to recognize Me, that I am Jehovah. Jeremiah 9:24.

In Hosea,

I will betroth you to Me in faith, and you will recognize Jehovah. Hosea 2:20.

[3] In these places 'recognizing' means perceiving, and perceiving comes about as a result of good, whereas understanding and seeing come about as a result of truth. For inwardly within themselves those in whom good or love is predominant perceive that something is so, whereas within themselves those in whom truth or faith is predominant see that it is such. Therefore perception that something is so exists among those who are in the Lord's celestial kingdom, but belief that it is so among those who are in the Lord's spiritual kingdom, see the places referred to in 9277, and what has been stated in 9992, 9995, 10105. And what perception is, see 125, 371, 483, 495, 503, 521, 536, 597, 607, 1121, 1384, 1387, 1398, 1442, 1919, 2144, 2515, 2831, 3528, 5121, 5145, 5227, 7680, 7977, 8780.

[4] In addition, since the proper meaning of 'recognizing' is perceiving as a result of good, reference is made in Deuteronomy 8:5 to recognizing from the heart; for 'from the heart' means from the good of love, 3883-3896, 7542, 9050, 9300, 9495. Therefore also doing good is referred to as recognizing Jehovah, Jeremiah 22:16.

From all this it is evident that 'they will recognize that I am Jehovah their God' means perception that the Lord is the source of all goodness and truth.